Get a 'Mobile Broadband Disconnected' error when change to 'WCDMA All' (3G)

I am trying to change my device to 3G, because 3G speeds are sometimes faster in my area. On my last Netgear Aircard with the same sim (Zain KW) I was able to switch to 3G. Now when I try switching to WCDMA All (3G) on my MR1100 Nighthawk, I get a 'Mobile Broadband Disconnected' error. Is there any way to fix this?